JP5030699B2 - Method and apparatus for adjusting thickness measuring apparatus - Google Patents

Description

  The present invention is applied to a thickness measuring device that measures the thickness of an object to be measured with a plurality of opposed laser distance meters, for example, a finishing line or an inspection line of a thick steel plate or a thin steel plate. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjustment method and apparatus for a thickness measuring apparatus including a laser distance meter, and in particular, a relative positional relationship between opposed laser distance meters that causes an error in measuring a plate thickness (dimension). The present invention relates to a technique for accurately detecting, adjusting, and configuring a deviation.

For thick plate and thin plate lines, it is necessary to continuously measure the plate thickness of steel plates that are continuously conveyed and passed, and to control and guarantee the plate thickness. Conventionally, γ rays, X-rays, etc. are used. A thickness gauge is used.
The γ-ray and X-ray thickness gauge measures the thickness of an object from the amount of attenuation of γ-rays and X-rays that pass through the object (steel plate), and is not easily affected by disturbances. It has been established as a technology that enables accurate thickness measurement.

  With these γ-ray and X-ray system thickness gauges, the beam shape of γ-rays and X-rays cannot be narrowed down, so only an average plate thickness with a certain area (beam cross-sectional area) can be measured. Furthermore, the responsiveness of the γ-ray and X-ray detectors is low, and with respect to an object (steel plate) that enters at high speed, the thickness of the tip portion cannot be measured accurately, resulting in a dead zone.

  On the other hand, a thickness gauge using a laser distance meter with high accuracy and high responsiveness utilizing the principle of triangulation has been put into practical use. This is to insert the object between the laser distance meters installed facing each other, and measure the thickness of the object from the distance between the distance meter and the measurement result of the distance to the object surface, Since the responsiveness is high and the measurement spot (laser beam diameter) is thin, it is possible to accurately measure the plate thickness over the entire length of the object to be conveyed at high speed.

  In addition, as an improvement technique, in order to reduce the thickness measurement error due to the vibration of the object to be measured and the deviation of the measurement position, a `` pulse modulator that emits a pulsed laser from the laser generator of the laser rangefinder, and An arithmetic unit that produces the thickness of the object to be measured, and a pulse generation circuit that generates a read start pulse to be transmitted to the image sensor, a laser oscillation pulse to be transmitted to the modulator, and an arithmetic start pulse to be transmitted to the arithmetic unit are provided. It is characterized by things. Is also disclosed (Patent Document 1).

JP-A-6-66525 (summary)

In the laser type thickness gauge, the object (steel plate) is calculated from the distance measurement result to the surface of the object (steel plate) inserted between the distance meters by the laser distance meter installed opposite to the distance between the opposing distance meters. Calculate the thickness. For this reason, it is necessary that the measurement axes of the distance meters facing each other are completely coincident with each other, and that state needs to be maintained during measurement.
If the measurement axes of the distance meters facing each other do not match or change occurs, an error occurs in the distance measurement value, and it becomes impossible to accurately measure the thickness of the object.

In an actual device, it is necessary to manufacture a frame and a pedestal for fixing and facing the distance meter, and to precisely adjust the positional relationship of the laser distance meter so that the measurement axis (optical axis) matches. At present, since the measurement points are confirmed by visual observation or the like and the angles of the frame and the case (horizontal and vertical) are adjusted, it is difficult to adjust with high accuracy, which is an error factor at the time of measurement.
In addition, it is difficult to confirm whether or not the installation and adjustment state is maintained, and it is difficult to perform readjustment by evaluating fluctuations and increase in errors associated with long-term use.

  The present invention has been made in order to solve the above-described problems, and in a thickness measurement apparatus including laser distance meters arranged opposite to each other, the angle and the position of the measurement axis of the laser distance meter are shifted. It is an object of the present invention to provide a method and apparatus for adjusting a thickness measuring device that can be evaluated and adjusted to eliminate an error factor and enable accurate thickness measurement.

An adjustment method for a thickness measuring apparatus according to the present invention is an adjustment method for a thickness measuring apparatus including a plurality of opposed laser distance meters, the angle of the laser distance meter with respect to the measurement direction, and the laser A plurality of calibration plates fixed at a distance from the distance meter and a cylindrical shape, and a plurality of calibration plates fixed in an annular shape along the cylindrical side surface, and can be rotated around a cylindrical rotation axis A single support part, a moving mechanism for moving the calibration piece support part and rotating it at a predetermined angle when moving each calibration plate within the measurement range of the laser rangefinder, and a measurement value of the laser rangefinder And calculating means for calculating and processing the thickness of each calibration plate in advance, and selecting two from the calibration plates (hereinafter referred to as the first calibration plate and the second calibration plate, respectively) The first calibration plate is moved to the laser distance A first measurement step of measuring the distance by moving the first calibration plate, a second measurement step of measuring the distance by moving the second calibration plate into the measurement range of the laser rangefinder, and the first measurement Based on the step of obtaining the difference between the distance measured in the step and the distance measured in the second measurement step, the distance between the first calibration plate and the second calibration plate, and the angle of the laser rangefinder with respect to the measurement direction. A step of calculating and predicting the difference, a step of obtaining an angle deviation of a measurement axis of the laser distance meter based on the difference, the difference calculated and calculated, and the angle, and the laser distance meter based on the angle deviation. Adjusting the measurement axis.

  Also, the thickness measuring device adjusting method according to the present invention selects one of the calibration plates (hereinafter referred to as a third calibration plate), and moves the third calibration plate within the measurement range of the laser distance meter. A third measuring step of measuring a distance from each of the opposed laser distance meters and measuring a thickness of the third calibration plate based on the measured value; and a thickness of the third calibration plate And a step of calculating and predicting a measured value of the thickness of the third calibration plate in the third measuring step based on the angle, a measured value of the thickness of the third calibration plate, the thickness of the calculated and predicted plate, And a step of obtaining a position deviation of the measurement axis of the laser distance meter based on the angle, and a step of adjusting the measurement axis of the laser distance meter based on the position deviation.

  Further, in the adjustment method of the thickness measuring apparatus according to the present invention, the respective steps are repeatedly executed for each calibration plate, and the measurement values by the laser distance meter at each repetition are averaged, or at each repetition. The deviation is averaged, and the measurement axis of the laser distance meter is adjusted based on the average value.

Further, the adjusting device of the thickness measuring device according to the present invention is an adjusting device of a thickness measuring device composed of a plurality of opposed laser distance meters, and measures the plate thickness in advance, and the laser distance meter A plurality of calibration plates that fix an angle with respect to the measurement direction and a distance from the laser rangefinder, and a cylindrical shape, and the plurality of calibration plates are fixed in an annular shape along the cylindrical side surface, and the cylindrical rotation A calibration piece support that is rotatable about an axis, and a moving mechanism that moves the calibration piece support when the calibration plates are moved within the measurement range of the laser rangefinder and rotates them at a predetermined angle. And a calculation means for calculating the measurement value of the laser distance meter, and the moving mechanism selects two of the calibration plates (hereinafter referred to as a first calibration plate and a second calibration plate, respectively) The first calibration plate and the second school The plate is sequentially moved within the measurement range of the laser distance meter, and the laser distance meter measures the distance each time the first calibration plate and the second calibration plate move within the measurement range of the laser distance meter. The calculating means obtains a difference between the distance between the first calibration plate and the distance between the second calibration plate and the distance between the first calibration plate and the second calibration plate measured by the laser distance meter, And calculating and predicting the difference based on the angle of the laser rangefinder with respect to the measurement direction , and obtaining an angle deviation of the measurement axis of the laser rangefinder based on the difference, the calculated and predicted difference, and the angle. .

  In the thickness measuring device adjusting apparatus according to the present invention, the moving mechanism selects one of the calibration plates (hereinafter referred to as a third calibration plate), and the third calibration plate is used as the laser distance meter. The laser distance meter is moved into a measurement range, and the laser distance meter measures the distance of the third calibration plate from each of the laser distance meters arranged opposite to each other, and the thickness of the third calibration plate is determined based on the measured value. The calculation means calculates and predicts a measurement value of the thickness of the third calibration plate by the laser distance meter based on the plate thickness of the third calibration plate and the angle, and The position deviation of the measurement axis of the laser rangefinder is obtained based on the measured value of the plate thickness, the plate thickness calculated and predicted, and the angle.

Further, the adjuster thickness measuring apparatus according to the present invention, before Symbol moving mechanism, the moves the rotary shaft, said rotary shaft is rotated, the measurement range of the laser rangefinder each said calibration plate Are moved sequentially.

  Further, in the adjusting device of the thickness measuring apparatus according to the present invention, each calibration plate is arranged on a straight line, and the moving mechanism sequentially moves each calibration plate within the measurement range of the laser distance meter. It is intended to reciprocate.

  Further, in the adjustment device of the thickness measuring apparatus according to the present invention, the laser distance meter measures the distance each time the moving mechanism moves each calibration plate within the measurement range of the laser distance meter, and performs the calculation. The means averages the measurement value by the laser distance meter for each calibration plate for each repetition, and the average value is used as the measurement result of the laser distance meter, or the deviation for each repetition is averaged. The average value is the deviation.

According to the present invention, in the thickness measuring device using a laser distance meter, it is possible to detect the relative position and direction deviation of the measurement axes of the laser distance meters arranged opposite to each other, and according to the detection result. By adjusting the position and direction of the laser rangefinder, it becomes possible to match the measurement axis of the laser rangefinder with high accuracy, which is caused by deviations in the measurement axis between the laser rangefinders (measurement position deviation, measurement direction deviation). The error factor is eliminated and accurate measurement is possible.
In addition, according to the present invention, mechanical deformation can be achieved by periodically detecting and confirming the relative positional relationship between the measurement axes of the laser distance meters arranged opposite to each other, and performing adjustment (calibration) as necessary. It is possible to correct the relative positional relationship of the laser rangefinder caused by distortion or the like and maintain highly accurate measurement conditions with reduced error factors.

Embodiment 1 FIG.
In the thickness measuring device adjustment method according to the first embodiment of the present invention, in the thickness measuring device configured by the laser distance meters arranged opposite to each other, the angle with respect to the measurement direction of the laser distance meter and the distance from the laser distance meter A plurality of calibration plates each having a fixed distance are provided, and a moving mechanism for moving these calibration plates into the measurement range of the laser rangefinder is provided, and distance measurement for each calibration plate is sequentially performed.
If there is a deviation in the measurement axis of the laser rangefinder, a deviation will occur between the measured value of the distance measurement with respect to each calibration plate and the predicted operation value. This makes it possible to detect the deviation of the measurement axis. .
In the following, the deviation between the measured value of the distance measurement for each calibration plate and the calculated predicted value will be described with reference to the drawings.

FIG. 1 is a diagram for explaining the reason why a measurement error occurs due to a deviation in the direction of a measurement axis during thickness measurement by a laser distance meter.
Two calibration plates (thicknesses are L1 and L2, L1> L2) with different thicknesses are sequentially inserted into the measurement range of the laser rangefinder, and the distance to the surface of the calibration plate is measured. At this time, the positions of the surfaces on which distance measurement is not performed are aligned.
As shown in FIG. 1A, when there is no deviation in the direction of the measurement axis, the difference ΔL1 between the measurement results for the two calibration plates is equal to the difference in plate thickness. That is, the following formula (1) is established.
ΔL1 = L1-L2 (1)
On the other hand, when there is a deviation of the angle θ in the direction of the measurement axis as shown in FIG. 1B, the difference ΔL2 in the measurement result is obtained by the following equation (2).
ΔL2 = (L1−L2) / cos (θ) (2)
Since L1 and L2 are known values, the direction of the measurement axis of the laser rangefinder can be adjusted so that the difference between ΔL1 and ΔL2 becomes small, and thereby the measurement deviation can be corrected. However, when the difference between L1 and L2 or θ is small, the difference between the left sides of Equation (1) and Equation (2) is also small, so there is a limit to the size of the adjustable direction deviation.

FIG. 2 is a diagram for explaining a measurement error when the distance measurement is performed in a state where the calibration plate is inclined at an angle α with respect to the measurement axis in FIG. When measuring the distance between the two calibration plates, the positions of the surfaces on which the distance measurement is not performed are aligned.
As shown in FIG. 2A, when there is no deviation in the direction of the measurement axis, the difference ΔL1 between the measurement results for the two calibration plates is obtained by the following equation (3).
ΔL1 = (L1−L2) / cos (α) (3)
On the other hand, when there is a deviation of the angle θ in the direction of the measurement axis as shown in FIG. 2B, the difference ΔL2 in the measurement result is obtained by the following equation.
ΔL2 = (L1−L2) / cos (α) +
(L1-L2) tan (θ) tan (α) / {1-tan (θ) tan (α)}
Furthermore, when θ is sufficiently small, it can be approximated as the following equation (4).
ΔL2≈ (L1-L2) / cos (α) +
(L1-L2) tan (θ) tan (α) (4)
Since L1, L2, and α are known values, the direction of the measurement axis of the laser rangefinder can be adjusted so that the difference between ΔL1 and ΔL2 becomes small, and thereby the measurement deviation can be corrected. In this case, although the values of L1 and L2 are the same as those in FIG. 1, the difference between ΔL1 and ΔL2 is larger than that in FIG. 1, so that the detection sensitivity to the direction deviation of the measurement axis is increased and more accurately. The direction deviation of the measurement axis can be detected.

In addition, the measurement of the direction of the laser distance meter on the opposite side can be detected by making the surface on which the distance is measured the opposite side and making the surface on which the distance measurement is not performed the opposite side.
Furthermore, by performing the measurement performed by the method described with reference to FIG. 2 in the same manner in the orthogonal direction, it is possible to detect the direction deviation of the measurement axes in the two orthogonal directions. The direction of the measurement axis can be adjusted accurately.

In the above description, an example has been described in which distance measurement is performed with the same inclination angle with respect to the measurement axis and the position of the surface on which distance measurement is not performed for two calibration plates having different plate thicknesses.
The measurement method is not limited to this, and two calibration plates having the same plate thickness and the same inclination angle with respect to the measurement axis are arranged at different known intervals with respect to the measurement direction. It is possible to simultaneously detect a deviation in the direction of the measurement axis of the laser distance meter.

  When inserting the two calibration plates into the measurement range of the laser rangefinder sequentially, there is a risk of error if this is done manually, so the angle of the calibration plate with respect to the measurement axis of the laser rangefinder, and It is desirable to configure the adjustment device so that the distance from the laser distance meter is determined, the calibration plate is fixed to the moving mechanism such as the frame at the angle and distance, and can be sequentially inserted into the measurement range of the laser distance meter. .

  As described above, according to the first embodiment, it is possible to detect the direction deviation of the measurement axes of the laser distance meters facing each other. In addition, by periodically performing detection and confirmation, and adjusting (calibrating) as necessary, the deviation of the relative positional relationship of the laser rangefinder caused by mechanical deformation, distortion, etc. is corrected, It is possible to maintain highly accurate measurement conditions with reduced error factors.

Furthermore, since the direction deviation of the measurement axis is detected using multiple calibration plates, unlike the method of detecting the direction deviation while moving a single calibration plate, the insertion conditions (tilt angle and insertion) of the calibration plate itself are different. It is not necessary to change the position) each time.
Therefore, it is possible to simplify the mechanism for moving the calibration plate within the measurement range of the laser rangefinder, and to detect with high accuracy without being affected by mechanical errors and setting errors caused by changes in the calibration plate insertion conditions. Can be performed.

Embodiment 2. FIG.
In the above-described first embodiment, the method of detecting the direction deviation of the measurement axis of the laser distance meter has been described.
In the second embodiment of the present invention, a method for detecting the positional deviation of the measurement axis of the laser distance meter, that is, the mismatch of the optical axes will be described.

  FIG. 3 is a diagram for explaining the reason why a measurement error occurs due to the displacement of the measurement axis when the thickness is measured by the laser distance meter. In FIG. 3, it is assumed that the direction deviation of the measurement axis is adjusted in advance by the method described in the first embodiment. The plate thickness d of the calibration plate is assumed to be known.

As shown in FIG. 3A, a calibration plate having a thickness d is inserted between the measurement ranges of the opposing laser distance meters. At this time, the measured value of the plate thickness matches the actual plate thickness d.
Next, as shown in FIG. 3B, when the calibration plate is tilted at an angle α with respect to the measurement axis, the measurement value L1 of the thickness of the calibration plate changes from the state of FIG. The value of L1 is expressed by the following equation (5).
L1 = d / cos (α) (5)
Here, as shown in FIG. 3 (c), in the measurement axis of the lower laser rangefinder, when the deviation of the distance h occurs with respect to the opposite optical axis, the thickness of the calibration plate is measured. The value L2 is expressed by the following formula (6).
L2 = d / cos (α) + h · tan (α) (6)
Since the thickness d and the angle α of the calibration plate are known, the value of the deviation h can be calculated from the measured value L2 and these values.

By the way, there may be a case where the measurement axis is deviated in the direction indicated by (*) in FIG. 3C. In this case, the magnitude relationship between L1 and L2 is reversed. By performing measurement while changing the inclination direction of the calibration plate, it is possible to easily grasp the direction of displacement of the measurement axis and the inclination of the calibration plate.
The same applies to FIG. 2B of the first embodiment.

  In addition, by performing the above-described measurement in the same manner in the orthogonal directions, it is possible to detect the positional deviation of the measurement axes in the two orthogonal directions, so the optical axis of the measurement axis of the opposing laser distance meter Can be matched exactly.

  Note that the distance of the calibration plate is measured with an inclination angle of 0 (perpendicular to the measurement axis), and then the distance of the calibration plate tilted at an angle α with respect to the measurement axis is measured, and the difference between the two is compared. Thus, in the subsequent measurement, the measurement direction position variation error can be canceled and the deviation of the measurement position can be easily calculated.

  As described above, according to the second embodiment, after adjusting the direction deviation of the measurement axis of the laser distance meter by the method described in the first embodiment, the position deviation of the measurement axis is further adjusted to be matched. As a result, the optical axes of the laser distance meters arranged opposite to each other can be made to coincide with each other with high accuracy, and it is possible to maintain highly accurate measurement conditions with reduced factors of plate thickness (dimension) measurement. .

Example 1.
FIG. 4 is a diagram illustrating the configuration of the adjusting device of the thickness measuring device according to the first embodiment of the present invention. 4A is a side view, and FIG. 4B is a plan view.
In the figure, 1 is a laser distance meter, 2 is a C frame for holding the laser distance meter 1, 3 is a guide for moving the frame, 4 is a calibration mechanism section, 5 is a calibration plate section, and 6 is a calibration section. A moving mechanism, 7 is a signal processing device, and 8 is a steel plate (target material) to be measured.

In the first embodiment, the C frame 2 is movable in the lateral direction in FIG. 4 along the guide 3 and is movable between a position where the target material 8 is measured and a position where calibration / adjustment is performed.
When the C frame 2 is moved to the “measurement position” in FIG. 4A by the calibration unit moving mechanism 6, the plate thickness of the target material 8 is measured by the laser distance meter 1 as described later with reference to FIG. 5.
When calibration / adjustment is performed, the C frame 2 is moved in the horizontal direction of FIG. 4 by the calibration unit moving mechanism 6 so that the laser rangefinder 1 is positioned at the “calibration / adjustment position” in FIG. The entire mechanism around the calibration plate 5 is moved in the vertical direction of FIG. 4B by the calibration mechanism 4 so that the calibration plate 5 comes between the laser distance meters 1.
Note that when the C frame 2 moves to the “measurement position”, the mechanism around the calibration plate 5 is retracted so as not to obstruct the movement.

The “movement mechanism” in the first embodiment corresponds to the calibration mechanism unit 4 and the calibration unit movement mechanism 6.
Further, the “calculation means” corresponds to the signal processing device 7. The signal processing device 7 can be configured by a computer or the like provided with an arithmetic device such as a CPU.

FIG. 5 is a side view when the C frame 2 is moved to the “measurement position”.
When the C frame 2 is moved to the “measurement position” in FIG. 4A by the calibration unit moving mechanism 6 and the target material 8 is inserted into the measurement range of the laser rangefinder 1, the upper and lower laser rangefinders facing each other. From the respective measurement distances (L1, L2) from 1 to the surface (front and back) of the target material 8 and the distance between the laser distance meters 1 (L0 = 640 mm), the dimension (plate thickness) of the target material 8 can be known.
The laser distance meter 1 outputs the measurement value to the signal processing device 7, and the signal processing device 7 performs the actual calculation process.

FIG. 6 illustrates the principle of the laser distance meter 1.
The laser rangefinder 1 projects laser light onto an object, detects reflected / scattered light on the surface of the object with a lens and a CCD line sensor, and calculates the distance to the object based on the principle of triangulation. The projection axis (optical axis) of the laser beam is the distance measurement direction.

FIG. 7 is a diagram illustrating how the angle / position adjustment of the laser rangefinder 1 is performed.
The laser distance meter 1 in the first embodiment has a measurement reference distance of 270 mm and a measurement range of 150 mm, and is fixed to the C frame 2 so that the distance L0 = 640 mm between the laser distance meters facing each other (wrapping the measurement range). Has been.
The C frame 2 includes a mechanism (not shown) for adjusting a fixed position and angle of the fixed laser distance meter with respect to the C frame, and each laser distance meter is arranged in two orthogonal directions (X (Axial direction, Y-axis direction) can be adjusted in position by ± 2 mm, and angle adjustment by ± 1 ° with respect to the vertical direction.

FIG. 8 is a diagram illustrating the configuration of the calibration plate unit 5.
The calibration plate portion 5 is configured such that the cylindrical calibration piece support portion 10 can rotate around the central axis 11. A plurality of plate-like calibration pieces 9 are fixed to the cylindrical side surface of the calibration piece support 10 in an annular shape along the circumference.
Each calibration piece is fixed at an angle with respect to the horizontal plane, and the inclination angles of all the calibration pieces are kept the same. Further, a level difference is provided at the fixing position of each calibration piece, and the height from the bottom of each calibration piece is different.
In the first embodiment, three kinds of calibration pieces 9 having a width of 25 mm and a length of 30 mm are provided with plate thicknesses of 5 mm, 25 mm, and 50 mm, and these are fixed to the side surface of a cylinder having a diameter of 250 mm as described above. The inclination of each calibration piece is inclined so as to become lower toward the outer peripheral side of the cylinder, and the inclination angle is set to 25 ° with respect to the horizontal plane.

FIG. 9 shows a state in which the inclination direction of the calibration piece 9 is adjusted.
Since each calibration piece 9 is fixed while maintaining the same inclination direction, it is necessary to move and rotate the entire calibration plate 5 in order to change the inclination direction at the measurement position.
For example, in FIG. 9A, the calibration piece 9 within the measurement range of the laser rangefinder 1 is tilted toward the lower left direction in FIG. 9, but is measured with the same calibration piece tilted in the lower right direction. 9B, it is necessary to move the entire calibration plate portion 5 to the left by the calibration portion moving mechanism 6 and to rotate it 180 ° about the central axis 11 as shown in FIG. 9B.
Similarly, if the center axis 11 is rotated by 90 °, measurement can be performed on the calibration piece 9 that is inclined in a direction orthogonal to the direction shown in FIG. The vertical movement is performed by the calibration mechanism unit 4. Alternatively, instead of rotating 90 °, the entire calibration plate 5 may be moved so that the calibration piece at the position rotated 90 ° is within the measurement range of the laser distance meter.

  Next, the calibration / adjustment process of the measurement axis direction deviation in the first embodiment will be described step by step.

(Process 1)
The C frame 2 is moved to the “calibration / adjustment position” in FIG. 4 by the calibration unit moving mechanism 6.
(Process 2)
The position of the calibration plate unit 5 in the vertical direction (in FIG. 4B) is moved within the measurement range of the laser rangefinder 1 by the calibration mechanism unit 4.
(Process 3)
The calibration plate unit 5 is rotated around the rotation shaft 11. With the rotation, each calibration piece 9 is sequentially inserted into the measurement range of the laser rangefinder 1.
(Process 4)
The measurement of the upper and lower laser distance meters 1 is started.
(Process 5)
The distance to the surface of the calibration piece 9 is measured by the upper and lower laser distance meters 1.
Hereinafter, the calibration piece number is n, the measurement distance by the upper laser distance meter is Lun, and the measurement distance by the lower laser distance meter is Ldn (n is the calibration piece number described above).
(Step 6)
Measurement is sequentially performed on the two calibration pieces with the calibration piece numbers n = 1 and 2, and the difference between the measurement value for the first calibration piece and the measurement value for the second calibration piece is obtained. The calculation processing is performed by the signal processing device 7.
If the difference between the measurement values of the upper laser distance meter is ΔLu1, and the difference between the measurement values of the lower laser distance meter is ΔLd1, they can be expressed by the following equations, respectively.
ΔLu1 = Lu2−Lu1
ΔLd1 = Ld2−Ld1
(Step 7)
The measurement by the laser distance meter 1 is stopped, and the rotation of the calibration piece 9 is stopped.
Next, the position of the calibration plate part 5 is moved by the calibration mechanism part 4 and the calibration part moving mechanism 6 so that the measurement of the calibration piece inclined in the direction orthogonal to the inclination direction of the calibration piece measured in step 6 can be executed. The calibration piece at a position rotated by 90 ° from the calibration piece measured in step 6 is set within the measurement range of the laser distance meter 1.
(Process 8)
The rotation of the calibration plate 5 and the measurement by the laser distance meter 1 are started, and the measurement is performed sequentially for two calibration pieces with the same calibration piece number n = 1, 2 as in step 6. Next, as in step 6, the difference between the measured value for the first calibration piece and the measured value for the second calibration piece is obtained. The calculation processing is performed by the signal processing device 7.
If the difference between the measured values of the upper laser distance meter is ΔLu2, and the difference between the measured values of the lower laser distance meter is ΔLd2, they can be expressed by the following equations, respectively.
ΔLu2 = Lu2-Lu1
ΔLd2 = Ld2−Ld1
(Step 9)
Based on the inclination angle of the calibration piece and the insertion position (height) of the calibration piece, a predicted operation value ΔL corresponding to ΔLu1 to ΔLd2 is obtained by the following equation. The calculation processing is performed by the signal processing device 7.
ΔL = L / cos (α)
ΔL: a value predicted as a difference between measured values of the first calibration piece and the second calibration piece L: difference in height between the first calibration piece and the second calibration piece α: inclination angle of the calibration piece (process 10)
When ΔL ≠ ΔLu1 or ΔL ≠ ΔLu2, it can be seen that the direction of the measurement axis of the upper laser rangefinder is shifted.
When ΔL ≠ ΔLd1 or ΔL ≠ ΔLd2, it can be seen that the direction of the measurement axis of the lower laser rangefinder is shifted.
FIG. 10 shows the relationship between the direction of deviation of the measurement axis and the direction of inclination of the calibration piece for detecting it.
As shown in FIG. 10A, when it is detected that the measurement axis of the laser rangefinder 1 is shifted around the X axis, measurement is performed on a calibration piece inclined with respect to the Y axis. As shown in FIG. 10B, when detecting that the measurement axis of the laser rangefinder 1 is shifted around the Y axis, measurement is performed on a calibration piece inclined with respect to the X axis.
(Step 11)
The mounting angle is adjusted so that the measurement directions of the laser distance meters are parallel.
(Step 12)
Steps 1 to 11 are repeated to check the angle adjustment result.

As described above, according to the first embodiment, a plurality of calibration plates are fixed to the cylindrical side surface to detect the direction deviation of the measurement axis. Therefore, the method of detecting the direction deviation while moving the single calibration plate, In contrast, it is not necessary to change the insertion conditions (inclination angle and insertion position) of the calibration plate itself.
Therefore, highly accurate detection can be performed without being affected by mechanical errors and setting errors associated with changes in the calibration plate insertion conditions.

Example 2
In the second embodiment of the present invention, the calibration / adjustment process of the positional deviation of the measurement axis will be described step by step.

(Process 1)
The calibration / adjustment of the measurement axis direction deviation described in the first embodiment is performed.
(Step 2) to (Step 4)
Since it is the same as the process 2 to the process 4 described in the first embodiment, the description is omitted.
(Process 5)
The distance to the surface of the calibration piece 9 is measured by the upper and lower laser distance meters 1. The distance measured by the upper laser distance meter is Lu, and the distance measured by the lower laser distance meter is Ld.
(Step 6)
From the measured value in step 5, the measured value D1 of the thickness of the calibration piece is calculated. The calculation processing is performed by the signal processing device 7.
D1 = L0-Lu-Ld
L0: Distance between upper and lower laser rangefinders (= 640 mm)
(Step 7)
Since it is the same as the process 7 demonstrated in Example 1, description is abbreviate | omitted.
(Process 8)
The rotation of the calibration plate 5 and the measurement by the laser distance meter 1 are started, and the same calibration piece as in the step 6 is measured. Next, as in step 6, a measurement value D2 of the plate thickness of the calibration piece is calculated. The calculation processing is performed by the signal processing device 7.
D2 = L0-Lu-Ld
(Step 9)
From the inclination angle of the calibration piece and the thickness of the calibration piece, a predicted operation value D0 corresponding to D1 and D2 is obtained by the following equation. The calculation processing is performed by the signal processing device 7.
D0 = d / cos (α)
D0: Value predicted as a measurement value of the thickness of the calibration piece d: Plate thickness of the calibration piece α: Inclination angle of the calibration piece (step 10)
When D0 ≠ D1 or D0 ≠ D2, it can be seen that the optical axes of the upper and lower laser distance meters do not coincide.
FIG. 11 shows the relationship between the direction of displacement of the measurement axis and the inclination direction of the calibration piece for detecting it.
As shown in FIG. 11A, when it is detected that the measurement axis of the laser rangefinder 1 is shifted in the direction along the Y axis, measurement is performed on a calibration piece inclined with respect to the Y axis. . Further, as shown in FIG. 11B, when detecting that the measurement axis of the laser rangefinder 1 is shifted in the direction along the X axis, the measurement is performed on the calibration piece inclined with respect to the X axis. I do.
(Step 11)
The mounting position on the C frame 2 is adjusted so that the optical axes of the laser distance meters coincide.
(Step 12)
Steps 2 to 11 are repeated, and the position adjustment result is confirmed.

As described above, according to the second embodiment, a plurality of calibration plates are fixed to the side surface of the cylinder and the positional deviation of the measurement axis is detected. Therefore, the method of detecting the positional deviation while moving the single calibration plate, In contrast, it is not necessary to change the insertion conditions (inclination angle and insertion position) of the calibration plate itself.
Therefore, highly accurate detection can be performed without being affected by mechanical errors and setting errors associated with changes in the calibration plate insertion conditions.

In the configuration described in the first and second embodiments, a plurality of calibration pieces are attached to the side surface of the cylinder and rotated to continuously vary measurement conditions (direction of inclination of the calibration piece, plate thickness, insertion position). Since the measurement of the calibration piece can be repeated, the measurement values can be averaged, and the detection system for the measurement direction deviation and the measurement position deviation can be improved.
When averaging the measured values, the measured values for the same calibration piece may be averaged to improve the detection accuracy for the calibration piece, or the deviations obtained for different calibration pieces may be obtained. The sum of the values may be averaged to improve the detection accuracy of the final deviation value.

  Moreover, in Examples 1-2, although the calibration piece was arrange | positioned on the cylindrical side surface, a plurality of calibration pieces with different plate thicknesses and inclination directions are arranged on a straight line, and a laser is reciprocated linearly in the arrangement direction. It is also possible to perform the same calibration / adjustment by sequentially inserting calibration pieces at the measurement position of the distance meter.

It is a figure explaining the reason a measurement error arises by the direction shift of a measurement axis at the time of thickness measurement by a laser distance meter. It is a figure explaining the measurement error at the time of implementing distance measurement in the state which inclined the angle (alpha) with respect to the measurement axis | shaft in FIG. It is a figure explaining the reason a measurement error arises by position shift of a measurement axis at the time of thickness measurement by a laser distance meter. It is a figure which shows the structure of the adjustment apparatus of the thickness measuring apparatus which concerns on Example 1. FIG. It is a side view when the C frame 2 has moved to the “measurement position”. The principle of the laser distance meter 1 will be described. It is a figure which shows a mode that angle / position adjustment of the laser distance meter 1 is performed. It is a figure which shows the structure of the calibration board part. The state in which the inclination direction of the calibration piece 9 is adjusted is shown. It is a figure explaining the relationship between the direction of the shift | offset | difference of a measurement axis | shaft, and the inclination direction of the calibration piece for detecting it. It is a figure explaining the relationship between the direction of the position shift of a measurement axis | shaft, and the inclination direction of the calibration piece for detecting it.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Laser distance meter, 2 C frame, 3 guide, 4 Calibration mechanism part, 5 Calibration board part, 6 Calibration part moving mechanism, 7 Signal processing apparatus, 8 Steel plate, 9 Calibration piece, 10 Calibration piece support part, 11 Central axis.

Claims (8)

A method for adjusting a thickness measuring device composed of a plurality of laser distance meters arranged opposite to each other,
A plurality of calibration plates that fix the angle with respect to the measurement direction of the laser distance meter and the distance from the laser distance meter;
A calibration piece support that is cylindrical and has a plurality of calibration plates fixed in an annular shape along a cylindrical side surface, and is rotatable about a cylindrical rotation axis;
When moving each calibration plate within the measurement range of the laser distance meter, the moving mechanism for moving the calibration piece support and rotating it at a predetermined angle;
A computing means for computing the measured value of the laser distance meter;
Provided,
Measure the thickness of each calibration plate in advance,
Select two of the calibration plates (hereinafter referred to as the first calibration plate and the second calibration plate, respectively)
A first measurement step of measuring the distance by moving the first calibration plate within the measurement range of the laser distance meter;
A second measurement step of measuring the distance by moving the second calibration plate within the measurement range of the laser rangefinder;
Obtaining a difference between the distance measured in the first measurement step and the distance measured in the second measurement step;
Calculating and predicting the difference based on a distance between the first calibration plate and the second calibration plate and an angle with respect to a measurement direction of the laser rangefinder ;
Obtaining an angular deviation of the measurement axis of the laser rangefinder based on the difference, the calculated and predicted difference, and the angle;
Adjusting the measurement axis of the laser rangefinder based on the angular deviation;
A method for adjusting a thickness measuring apparatus, comprising: Select one of the calibration plates (hereinafter referred to as the third calibration plate),
The third calibration plate is moved within the measurement range of the laser distance meter, and the distance from each of the laser distance meters arranged opposite to each other is measured, and the thickness of the third calibration plate is determined based on the measured value. A third measuring step to measure,
Calculating and predicting the measured value of the thickness of the third calibration plate in the third measurement step based on the thickness of the third calibration plate and the angle; and
Obtaining a positional deviation of the measurement axis of the laser distance meter based on the measured value of the thickness of the third calibration plate, the calculated predicted thickness, and the angle;
Adjusting the measurement axis of the laser distance meter based on the position deviation;
The method of adjusting a thickness measuring apparatus according to claim 1, wherein: Repeat each step for each calibration plate,
Average the measured values by the laser distance meter for each iteration, or average the deviation for each iteration,
The method for adjusting a thickness measuring apparatus according to claim 1 or 2, wherein the measuring axis of the laser distance meter is adjusted based on the average value. An adjustment device for a thickness measuring device composed of a plurality of opposed laser distance meters,
A plurality of calibration plates that measure the plate thickness in advance and fix the angle with respect to the measurement direction of the laser distance meter and the distance from the laser distance meter,
A calibration piece support that is cylindrical and has a plurality of calibration plates fixed in an annular shape along a cylindrical side surface, and is rotatable about a cylindrical rotation axis;
When moving each calibration plate within the measurement range of the laser distance meter, the moving mechanism for moving the calibration piece support and rotating it at a predetermined angle;
A computing means for computing the measured value of the laser distance meter;
With
The moving mechanism is
Two are selected from the calibration plates (hereinafter referred to as a first calibration plate and a second calibration plate, respectively), and the first calibration plate and the second calibration plate are sequentially moved into the measurement range of the laser rangefinder. ,
The laser distance meter
Measuring the distance each time the first calibration plate and the second calibration plate move within the measurement range of the laser rangefinder;
The computing means is
The difference between the distance of the first calibration plate and the distance of the second calibration plate measured by the laser distance meter is obtained,
Based on the distance between the first calibration plate and the second calibration plate and the angle with respect to the measurement direction of the laser rangefinder , the difference is calculated and predicted,
An adjustment device for a thickness measuring apparatus, wherein an angle deviation of a measurement axis of the laser distance meter is obtained based on the difference, the calculated and predicted difference, and the angle. The moving mechanism is
Select one of the calibration plates (hereinafter referred to as the third calibration plate),
Moving the third calibration plate within the measurement range of the laser distance meter;
The laser distance meter
Measure the distance of the third calibration plate from each of the laser distance meters arranged opposite to each other, measure the thickness of the third calibration plate based on the measured value,
The computing means is
Based on the plate thickness of the third calibration plate and the angle, the measurement value by the laser distance meter of the plate thickness of the third calibration plate is calculated and predicted,
5. The thickness according to claim 4, wherein a positional deviation of a measurement axis of the laser distance meter is obtained based on a measured value of the thickness of the third calibration plate, the calculated predicted thickness, and the angle. Measuring device adjustment device. The moving mechanism is
While moving the rotating shaft, rotating the rotating shaft,
Each of the said calibration plates is moved sequentially within the measurement range of the said laser distance meter. The adjustment apparatus of the thickness measuring device of Claim 4 or Claim 5 characterized by the above-mentioned. Each calibration plate is arranged on a straight line,
The moving mechanism is
The adjusting device for a thickness measuring apparatus according to claim 4 or 5, wherein the calibration plates are sequentially reciprocated within a measurement range of the laser distance meter. The laser distance meter
Each time the moving mechanism moves each calibration plate within the measurement range of the laser distance meter, the distance is measured,
The computing means is
The measurement value by the laser distance meter for each calibration plate is averaged for each repetition, and the average value is the measurement result of the laser distance meter,
Or
The adjustment device for a thickness measuring device according to any one of claims 4 to 7, wherein the deviation for each repetition is averaged and the average value is used as the deviation.

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